Moscow: Russian President Vladimir Putin has signed the ratification of an agreement with the United States that substantially eases the visa regime for both countries' citizens.

The agreement allows Russians and Americans to get three-year multi-entry visas under which they can stay for up to six consecutive months. It also eliminates Russia's requirement that visitors get a letter of invitation, although tourists will still need to show advance accommodation bookings.

Easing the laborious and limiting visa system is expected to boost business contacts between the countries and improve tourism, particularly of Americans coming to Russia.

Although Putin's signing was announced on Monday, the new measures will not go into effect until after both countries exchange notes certifying that preparations for the changes have been completed.